Numerical Analysis and Scientific Computing Commons^™

Fast Multipole Methods For Wave And Charge Source Interactions In Layered Media And Deep Neural Network Algorithms For High-Dimensional Pdes, Wenzhong Zhang

Mathematics Theses and Dissertations

In this dissertation, we develop fast algorithms for large scale numerical computations, including the fast multipole method (FMM) in layered media, and the forward-backward stochastic differential equation (FBSDE) based deep neural network (DNN) algorithms for high-dimensional parabolic partial differential equations (PDEs), addressing the issues of real-world challenging computational problems in various computation scenarios.

We develop the FMM in layered media, by first studying analytical and numerical properties of the Green's functions in layered media for the 2-D and 3-D Helmholtz equation, the linearized Poisson--Boltzmann equation, the Laplace's equation, and the tensor Green's functions for the time-harmonic Maxwell's equations and the …

A Fast Method For Computing Volume Potentials In The Galerkin Boundary Element Method In 3d Geometries, Sasan Mohyaddin

Mathematics Theses and Dissertations

We discuss how the Fast Multipole Method (FMM) applied to a boundary concentrated mesh can be used to evaluate volume potentials that arise in the boundary element method. If $h$ is the meshwidth near the boundary, then the algorithm can compute the potential in nearly $\Ord(h^{-2})$ operations while maintaining an $\Ord(h^p)$ convergence of the error. The effectiveness of the algorithms are demonstrated by solving boundary integral equations of the Poisson equation.

Ensemble Data Fitting For Bathymetric Models Informed By Nominal Data, Samantha Zambo

Dissertations

Due to the difficulty and expense of collecting bathymetric data, modeling is the primary tool to produce detailed maps of the ocean floor. Current modeling practices typically utilize only one interpolator; the industry standard is splines-in-tension.

In this dissertation we introduce a new nominal-informed ensemble interpolator designed to improve modeling accuracy in regions of sparse data. The method is guided by a priori domain knowledge provided by artificially intelligent classifiers. We recast such geomorphological classifications, such as ‘seamount’ or ‘ridge’, as nominal data which we utilize as foundational shapes in an expanded ordinary least squares regression-based algorithm. To our knowledge …

The Foundations Of Inference And Its Application To Fundamental Physics, Nicholas Matthew Carrara

Legacy Theses & Dissertations (2009 - 2024)

This thesis concerns the foundations of inference – probability theory,entropic inference, information geometry, etc. – and its application to the Entropic Dynamics (ED) approach to Quantum Mechanics (QM) [21, 22, 41, 53, 56–61, 150–153, 165, 195, 196, 268]. The first half of this thesis, chapters 2-6, concern the development of the inference framework. We begin in chapter 2 by discussing de- ductive inference, which involves formal logic and it’s role in access- ing the truth of propositions. We eventually discover that deductive inference is incomplete, in that it can’t address situations in which we have incomplete information. This necessitates a …

Learning To Assign: Towards Fair Task Assignment In Large-Scale Ride Hailing, Dingyuan Shi, Yongxin Tong, Zimu Zhou, Bingchen Song, Weifeng Lv, Qiang Yang

Research Collection School Of Computing and Information Systems

Ride hailing is a widespread shared mobility application where the central issue is to assign taxi requests to drivers with various objectives. Despite extensive research on task assignment in ride hailing, the fairness of earnings among drivers is largely neglected. Pioneer studies on fair task assignment in ride hailing are ineffective and inefficient due to their myopic optimization perspective and timeconsuming assignment techniques. In this work, we propose LAF, an effective and efficient task assignment scheme that optimizes both utility and fairness. We adopt reinforcement learning to make assignments in a holistic manner and propose a set of acceleration techniques …

Vehicle Routing: Review Of Benchmark Datasets, Aldy Gunawan, Graham Kendall, Barry Mccollum, Hsin-Vonn Seow, Lai Soon Lee

Research Collection School Of Computing and Information Systems

The Vehicle Routing Problem (VRP) was formally presented to the scientific literature in 1959 by Dantzig and Ramser (DOI:10.1287/mnsc.6.1.80). Sixty years on, the problem is still heavily researched, with hundreds of papers having been published addressing this problem and the many variants that now exist. Many datasets have been proposed to enable researchers to compare their algorithms using the same problem instances where either the best known solution is known or, in some cases, the optimal solution is known. In this survey paper, we provide a list of Vehicle Routing Problem datasets, categorized to enable researchers to have easy access …

Dynamic Lane Traffic Signal Control With Group Attention And Multi-Timescale Reinforcement Learning, Qize Jiang, Jingze Li, Weiwei Sun, Baihua Zheng

Research Collection School Of Computing and Information Systems

Traffic signal control has achieved significant success with the development of reinforcement learning. However, existing works mainly focus on intersections with normal lanes with fixed outgoing directions. It is noticed that some intersections actually implement dynamic lanes, in addition to normal lanes, to adjust the outgoing directions dynamically. Existing methods fail to coordinate the control of traffic signal and that of dynamic lanes effectively. In addition, they lack proper structures and learning algorithms to make full use of traffic flow prediction, which is essential to set the proper directions for dynamic lanes. Motivated by the ineffectiveness of existing approaches when …

Solving Large-Scale Extensive-Form Network Security Games Via Neural Fictitious Self-Play, Wanqi Xue, Youzhi Zhang, Shuxin Li, Xinrun Wang, Bo An, Chai Kiat Yeo

Research Collection School Of Computing and Information Systems

Securing networked infrastructures is important in the real world. The problem of deploying security resources to protect against an attacker in networked domains can be modeled as Network Security Games (NSGs). Unfortunately, existing approaches, including the deep learning-based approaches, are inefficient to solve large-scale extensive-form NSGs. In this paper, we propose a novel learning paradigm, NSG-NFSP, to solve large-scale extensive-form NSGs based on Neural Fictitious Self-Play (NFSP). Our main contributions include: i) reforming the best response (BR) policy network in NFSP to be a mapping from action-state pair to action-value, to make the calculation of BR possible in NSGs; ii) …

Computational Studies Of Carbon Nanocluster Solidification, Chathuri C. Silva

Dissertations

A subset of micron-size meteoritic carbon particles formed in red giant atmospheres show a core-rim structure, likely condensed from a vapor phase into super-cooled carbon droplets that nucleated graphene sheets (~40Å) on randomly oriented 5-atom loops during solidification, followed by coating with a graphite rim. Similar particles form during slow cooling of carbon vapor in the lab.

Here we investigate the nucleation and growth of carbon rings and graphene sheets using density functional theory (DFT). Our objectives: (1). explore different computational techniques in DFT-VASP for various carbon structures and compare the results with literature, (2). investigate the nucleation and growth …

Simulation Of Cooperative Control Process For Multiple Uavs Based On Local Information Connection, Xiangyang Li, Zhili Zhang, Zhang Ning, Gui Yi, Li Jia

Journal of System Simulation

Abstract: Aiming at the requirements of cooperative control for multiple UAVs based on local information connection, the distributed architecture of Multi-UAV system is established on the basis of multilayer structure. The communication network topology, state control information model and intelligent Ad-Hoc network mechanism are proposed to ensure the reliable interactive communication among multiple UAVs under local information connection. The cooperative collision avoidance strategy with local state prediction and distributed iterative optimization, combined with the cooperative on-line track planning and threat avoidance control methods, are applied to realize the cooperative control of Multi-UAV's task execution process. Simulation experiments verify the …

Research On Generating Technology For Equipment Standard Set Based On Uaf Modeling, Shuofang Zheng, Ruiheng He, Wenming Ren

Journal of System Simulation

Abstract: In order to meet the requirements of equipment standardization work of top-down design of current era, the modeling principles and methods of Unified Architecture Frame (UAF) are studied. Focus on the construction of four standard view models specified by UAF, Standards taxonomy, Standards structure, Standards roadmap, Standards traceability, the correlation model of operation perspective, requirement perspective and resource perspective are analyzed to form the requirement-driven equipment standard set generation technology. A new standard generation mechanism oriented to use scenarios and closely related to equipment development needs is established, and a new entry point for equipment standardization is proposed. The …

Study On Universal Characteristics Of Insect Population Ecological Network, Guilan Luo, Hongjun Hao, Wang Xiao, Zhang Mei

Journal of System Simulation

Abstract: In order to evaluate the current state of insect ecological development in Erhai wetland, complex network theory is used to construct a topological structure model of insect ecological network with insect populations as network nodes and correlations as edges. By analyzing the characteristic parameters of the model, it is concluded that the insect ecological network conforms to the characteristics of small world and scale-free network, and the node degree distribution obeys the power law distribution. The method of destroying the topology is used to simulate the dynamic evolution of the network ecology. The study shows that the disappearance of …

Research On Active Suspension Control Of High-Speed Train Based On Fuzzy Compound Strategy, Jianjun Meng, Zhongjun Wang, Ruxun Xu, Decang Li

Journal of System Simulation

Abstract: In order to improve the running stability of high-speed train, a semi-vertical six-degree-of- freedom state space model is established based on the active suspension system. Based on fuzzy control theory, the fuzzy controllers and fuzzy PID controllers are designed. Aiming at the defects of strong subjectivity of fuzzy PID control which needs manual adjustment, particle swarm optimization is used to optimize the initial parameters of the controller to make the suspension system be more correspond with the objective reality. In order to verify the advance of this strategy, with the sky-hook damping strategy for comparison, the controller model …

Study On Task Allocation Of Uav Swarm Based On Cognitive Control, Ruixuan Wei, Zichen Wu

Journal of System Simulation

Abstract: A centralized allocation method for Unmanned Aerial Vehicle (UAV) swarm real-time task allocation is proposed. Based on the real-time battlefield situation, this method relies on the coordination scheduling layer to make allocation decisions, generates the strike order according to the strike efficiency ratio, and makes rolling optimization for real-time battlefield situation, so that the allocation results can always maintain the balance between optimization and efficiency within the current cognitive range. Particle swarm optimization (PSO) is used to solve the task assignment problem. In particular, a 2-D particle 0-1 coding and correction method for nonstandard particles is designed. The simulation …

Uniform Experimental Design Of Constrained Region Based On Evolutionary Algorithm, Jianing Wei, Hao Hao, Qutong Chang, Lin Tao, Zhang Hu

Journal of System Simulation

Abstract: The parameters of a simulation system are usually generated by the experimental design. Aiming at high design difficulty and computational cost of the uniform experimental design, of the constraint region, a two-stage differential evolutionary algorithm is further improved. The design is modeled as a constrained optimization problem. A strategy combining distribution estimation algorithm (EDA) and differential evolution (DE) is adopted. A point-deletion method is proposed to reduce the time complexity of optimizing the population uniformity. To demonstrate the advantages, the test instances and engineering applications are used in experimental analysis. The experimental results show that the performance, stability, and …

Research On Agile Reentry Method For Maneuvering Vehicle, Lin Yue, Yingmin Jia, Songtao Fan

Journal of System Simulation

Abstract: Alarge-scale orbit maneuver method is proposed and analyzed for hypersonic space reentry vehicles, and the air assisted methods are adopted to conduct space orbit maneuvers by complying with the energy balance strategy of the aircraft. By the L/D ratio of aircraft, the efficiency of the propellant use during orbital maneuvers is elevated, and the maneuverability is also enhanced, while the risk of aircraft being tracked in space can be reduced. Aero-assisted guidance technology is applied based on full-coefficient adaptive prediction-correction technology which significantly simplifies the computation of the GNC computer, while such application ensures the convergence and enhances the …

Study On Interior Space Pedestrian Evacuation Model Elite Chaos Search Strategy, Wei Juan, Zhongyu Li, You Lei, Yangyong Guo, Zhihai Tang, Zhouyi Hu

Journal of System Simulation

Abstract: In order to improve traditional field model of easily falling into the queue problem during simulating the evacuation of dense crowds, an improved pedestrian evacuation model in interior space is proposed based on the elite chaos search strategy. The pedestrian mobile income at each moment is calculated in combination with the field value, capacity and average speed, and a field model for pedestrian evacuation is presented. On this basis, the objective optimization function of the minimum evacuation time and minimum queue length is given, and the elite chaos search strategy is used to achieve the above objective function solution, …

Research On Performance Modeling And Simulation Method Based On Dense Crowd, Yihao Li, Tianyu Huang, Li Peng, Gangyi Ding

Journal of System Simulation

Abstract: Due to the high complexity of crowd organization and the difficulty of abstracting the performance, the performance simulation of dense crowds relies heavily on manual work, and it is difficult to establish a highly automated simulation model. In order to reduce the sensitivity of creative modification and design risks, a performance model based on dense crowd is proposed. Through the strategy of time dimension slicing and spatial layering, a highly automated crowd performance simulation method that could meet the director's creativity is realized. Through the construction of simulation experiments, the generation effect and calculation efficiency of the crowd …

Fast Alignment Of Bim Products Based On Structure Matching, Xiaojun Liu, Changyan He, Liu Chang, Jinyuan Jia

Journal of System Simulation

Abstract: The fast alignment of BIM products based on structure matching is realized. An Item-based Structure Graph (ISG) is proposed as the structure-aware shape descriptor for BIM products. An improved graph matching algorithm upon Factorized Graph Matching (FGM) is implemented in ISG matching, in which the mismatch caused by symmetry switching is avoided. Further extension is made to support the alignment under partial matching for BIM products from the same family. The experiment result shows that ISG can meet the characteristics of BIM products, improve the efficiency and accuracy, and can be applied in dealing with products alignment, BIM data …

Design And Engine Implementation Of Submarine Combat System Simulation Based On Lvc, Jinping Wu, Minghua Lu, Changyou Xue

Journal of System Simulation

Abstract: Submarine combat system simulation is one of the key and most important content in submarine combat simulation. On the basis of LVC simulation technology, practicing simulation-as-a-service idea, the LVC integration simulation method of submarine combat system is proposed and the LVC integration simulation environment is constructed. The composition and relationship of LVC simulation system are researched. The compositional structure of LVC simulation engine was designed. Based on the component design and development specifications in Java/EJB technological infrastructure, in use of software component technology, the simulation engine components are designed and implemented. The LVC integration simulation of submarine combat system …